Refactor solution structure and update package versions

- Reorganized `SimpleAuthentication.sln` by removing duplicate project entries and adding structured folders for "Samples" and "Solution Items".
- Updated `Microsoft.AspNetCore.Authentication.JwtBearer` package versions in `SimpleAuthentication.Abstractions.csproj` for `net8.0` (8.0.19 to 8.0.20) and `net9.0` (9.0.8 to 9.0.9).
- Added `SimpleAuthentication.slnx` for a structured representation of the solution.

Author: marcominerva

SimpleAuthentication.sln

@@ -0,0 +1,22 @@
+<Solution>
+  <Folder Name="/Samples/" />
+  <Folder Name="/Samples/Controllers/">
+    <Project Path="samples/Controllers/ApiKeySample/ApiKeySample.csproj" />
+    <Project Path="samples/Controllers/BasicAuthenticationSample/BasicAuthenticationSample.csproj" />
+    <Project Path="samples/Controllers/JwtBearerSample/JwtBearerSample.csproj" />
+  </Folder>
+  <Folder Name="/Samples/Minimal APIs/">
+    <Project Path="samples/MinimalApis/ApiKeySample/ApiKeySample.csproj" />
+    <Project Path="samples/MinimalApis/BasicAuthenticationSample/BasicAuthenticationSample.csproj" />
+    <Project Path="samples/MinimalApis/JwtBearerSample/JwtBearerSample.csproj" />
+    <Project Path="samples/MinimalApis/Net8JwtBearerSample/Net8JwtBearerSample.csproj" />
+  </Folder>
+  <Folder Name="/Solution Items/">
+    <File Path=".editorconfig" />
+    <File Path=".github/copilot-instructions.md" />
+    <File Path="src/Directory.Build.props" />
+  </Folder>
+  <Project Path="src/SimpleAuthentication.Abstractions/SimpleAuthentication.Abstractions.csproj" />
+  <Project Path="src/SimpleAuthentication.Swashbuckle/SimpleAuthentication.Swashbuckle.csproj" />
+  <Project Path="src/SimpleAuthentication/SimpleAuthentication.csproj" />
+</Solution>

SimpleAuthentication.slnx

@@ -28,11 +28,11 @@
     </ItemGroup>
 
     <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
-        <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.19" />
+        <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.20" />
     </ItemGroup>
 
     <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
-        <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="9.0.8" />
+        <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="9.0.9" />
     </ItemGroup>
 
     <ItemGroup>